As a configuration where a seat surface of a vehicle seat is provided with a ventilation function, in the disclosure of Japanese Patent No. 3,835,329 (Patent Literature 1), air sent from an air sending unit is introduced from an introduction passage formed in a main seat material, into an air distribution passage on a groove formed in the surface of the main seat material on the sub seat material side, and the air is exhausted from a through hole formed in the sub seat material to the side of the seat surface material. The opening area of the through hole is set such that it is sequentially enlarged from the introduction passage toward the downstream end side of the air distribution passage.
Further, in the disclosure of Japanese Patent No. 3,956,513 (Patent Literature 2), air forcibly sent from an air sending unit is supplied, from the introduction passage through a communication port, to plural air distribution passages extending along a seat surface. The air distribution passage formed on the seat back side extends approximately linearly on both sides of the seat back in a vertical direction. At least one end of the air distribution passage is open in an end surface of the seat. The communication hole of the introduction passage is provided in a position as a part to receive an occupant's back as seating pressure.